How to make a screed for electric underfloor heating? A screed under a warm floor will provide not only energy savings, but also a quick warming up of a warm floor. Warm floor in the screed: the pros and cons Warm screed on the electric floor

The article was prepared with the participation of specialists from LafargeHolcim

The heating system "warm floor" is popular with both urban residents and owners country houses. This is due to the fact that, thanks to the optimal distribution of temperature vertically (from floor to ceiling), it helps to create comfortable conditions in the house. One of the options for underfloor heating can be electric, with a heating cable laid in a sand concrete screed. Many users have questions about how to make such a system correctly, avoid installation errors and pour reliable and durable sand concrete screed. In this article, we, with the help of a specialist from LafargeHolcim, will tell you:

• How to choose the right "pie" electric underfloor heating with a heating cable.
• What should be the thickness of the sand concrete screed when using a heating cable.
• How to choose high-quality sand concrete and cement.
• How to independently prepare a solution of sand and cement.
• Why is fiber added to sand concrete?
• The main stages of work on pouring sand concrete underfloor heating screed with a heating cable.

Features of electric underfloor heating with heating cable

Maria A FORUMHOUSE Member

I have a house with an unheated basement. Overlapping - concrete slabs. I want to make an electric underfloor heating on the ground floor in the kitchen and hallway under the tiles. I thought: what kind of warm floor should I choose, what layers does the right “pie” consist of. Do I need to lay insulation under the warm floor and what kind. How to make and fill the screed.

To answer these questions, you first need to understand the types of electric underfloor heating.

1. Film underfloor heating. It is laid directly ("dry") under the finishing floor covering - laminate, carpet or linoleum. Of the advantages, we note: the minimum thickness of the system and the high speed of installation. Cons - you can’t put such a warm floor under the tiles, in “wet rooms”, because. the film is afraid of moisture and aggressive alkaline media solutions - tile adhesive or screed based on sand concrete.

Finished flooring (e.g. laminate) must be certified for operation with underfloor heating and allow heating.

2. Heating mats (thermomats). This is a finished product with a certain, calculated cable pitch, in strong insulation, laid in a grid. This simplifies the calculation of the power of a warm floor and reduces the installation time of the entire system. Most often, heating mats are chosen when it is not possible to increase the height of the floor and pour a full-fledged screed, and the mats are mounted directly into the layer of tile adhesive.

Heating mats are produced with a certain width and heating area multiplicity of 0.5 m², 1 m², 2 m², etc.

For example, for dry insulated rooms and as a heating system, additional to the radiator, the power of thermomats is selected at the rate of 120 - 140 W / m². For the main heating system - at least 150 W / m². For rooms with high humidity and non-insulated rooms - 180 - 200 W / m².

The power of the heating system is calculated based on the heat loss of the house, which it must compensate.

3. Underfloor heating based on a heating (single-core or two-core) cable in a shielding braid, which minimizes the level of electromagnetic radiation.

A heating cable is usually cheaper than a thermomat. Using a cable, you can vary the power of the underfloor heating system by one square meter, adjusting the cable laying step on the mounting tape. Unlike heating mats laid in a thin layer (about 5 mm) of tile adhesive, the heating cable is embedded in a 3-6 cm thick cement (sand concrete) mortar screed, which accumulates heat well (inertia of the system increases).

The thicker the screed, the longer it cools down, but the longer it heats up, because. a heating cable laid in a sand concrete screed needs much more time to fully warm up the room and itself floor covering. When using heating mats located directly in the layer of adhesive under the tile, the heating of the coating (the system's output to the operating mode) occurs much faster.

Important: when choosing a floor heating system between thermomats and a heating cable, it should be remembered that the height of the floor (the thickness of the entire structure when using the cable) will be raised by at least 4.5 cm, taking into account the thickness of the screed (about 3 cm), tiles (1 cm) and tile adhesive (0.5 cm). It is possible to turn on a warm floor from heating mats already 10-14 days after laying the tile adhesive. When using a heating cable and a sand-concrete screed, this period increases to 21-28 days, because. sand concrete screed must gain the necessary strength.

The correct structure of the system ("pie") of a warm floor with a heating cable in a sand concrete screed

The "pie" of an electric underfloor heating with a heating cable depends on the characteristics of the heated room and the magnitude of its heat loss. To reduce heat loss, the base on which the underfloor heating is mounted must be well insulated. Otherwise, the low-temperature heating system will also heat the master's room, and at the same time the neighbor's ceiling (in a city apartment) or, through an uninsulated ceiling, an unheated basement or loggia.

At the stage of choosing the optimal "pie" of electric underfloor heating, users have a lot of questions.

Maria A

I'm wondering how to properly insulate underfloor heating. Is it necessary to roll out a foam polyethylene insulation over the screed, and is it necessary to lay the insulation under the screed.

boroda1965 FORUMHOUSE user

I thought about making underfloor heating. I think, insulate it with extruded polystyrene foam, roll out penofol on top, and then lay a warm floor and put porcelain stoneware on a solution with the addition of a plasticizer.

Practice shows that the use of foam insulation with a foil layer in the underfloor heating system is one of the most common mistakes. By using this material, users assume that the foil layer will reflect heat energy upwards. In fact the reflective effect of the foil does not work in solids, i.e. in concrete screed. The effect of heat flux reflection appears only in the presence of an air gap between the foil layer and finishing. A classic example is the insulation of a sauna, when a lining is mounted on the walls on the crate, and a gap of 2-3 cm is maintained between the foil and wood.

In addition, the usual the foil is destroyed (dissolved) in an alkaline environment concrete mortar or glue, and the foamed (soft) insulation shrinks (compacts) over time under the weight of the screed, which leads to cracks.

In the underfloor heating system, you need to use the so-called. multifoil- a special material in which the foil layer is protected from the negative effects of the alkaline environment of concrete with a layer of polyethylene.

Such a substrate for heating cable prevents direct contact of the heating element with the insulation(does not allow the cable to be pressed into the thermal insulation, which will cause its local overheating) and does not reflect, but distributes heat evenly in a screed. And, thereby, minimizes the so-called. the effect of "zebra" (uneven heating of the surface of the warm floor, when warm areas alternate with colder ones).

Hence, the optimal "pie" of a warm floor with a heating cable is as follows:

• Insulation is laid on a flat base, cleaned of dirt and dust. Optimally - EPS (extrusive polystyrene foam) with a thickness of at least 2 to, optimally, 3-5 cm.
• A damper is mounted along the perimeter of the walls. edging tape, which compensates for the thermal expansion of the sand concrete screed with a warm floor.

• A multifoil (if applicable) or a metal mesh is laid on the insulation, which also prevents the cable from contacting the insulation. Cell size: 25x25 mm or 50x50 mm. Bar diameter 1.6-3 mm.

• A mounting tape is rolled out from above, which is attached to the grid with plastic clamps. On the mounting tape, after maintaining the laying step (on average 10-12 cm), it is easier and faster to fix the heating cable, fixing it in the locks, but you can do without it, in this case the cable is attached to the grid with plastic clamps.

The step of laying the heating cable (power of the warm floor per 1 sq. M.) Is calculated based on the area of ​​​​the room and the length of the cable.

In order for the metal mesh to start working (it reinforced the screed, being in the thickness of the sand concrete, and not under it), you need to raise it above the thermal insulation layer using stands or small pieces of XPS. Or, as an option, lay a second layer of mesh on the cable, for greater reinforcement.

• After laying the heating cable and the temperature sensor, which should be in the "body" of the screed, the system is checked for visible damage to the cable and the electrical part is tested. Next, beacons are set up and a screed with a thickness of 3 to 6 cm is poured.

Anna Ruzhitskaya

The screed is poured from the wall opposite the entrance to the room. It should be remembered that when leveling highly mobile or cast ties, spiked rollers should not be used, which can damage the cables.

The nuances of choosing high-quality sand concrete and cement in bags and the features of pouring the screed

To the stage of pouring the screed, the so-called. "Wet type" some developers are not responsible enough, making mistakes when choosing a ready-made sand concrete mix M300 or violating the proportions when preparing the solution on their own. For example, a lot of water is used to give the mixture greater mobility and increase its life during installation, which leads to a decrease in the strength of the screed and an increase in the likelihood of cracks.

Maria A

I want to make my own mix for pouring sand concrete screed. Questions: how to choose the components of the mixture and what additives are better to use?

Another frequently asked question portal users: which is better - use ready-made sand concrete or independently prepare a mixture of high-quality cement in bags.

Anna Ruzhitskaya

In terms of convenience, reliability and stability of the result, it is better to use ready-made dry mixes (sand concrete). For these mixtures, it is regulated maximum size grains of sand, i.e. seeded sand is used in production, the proportions of cement-sand are clearly maintained and the parameters for crack resistance of the hardened mortar are checked.

Note that the mixtures from trusted manufacturers undergo rigorous quality control at all stages of production and meet all the requirements of GOST. Precisely measured by weight, the mixture is delivered to the object in reliable packaging - 40 kg bags.

For a screed device on a warm floor, it is better to use a “wet” screed.

A semi-dry screed differs from a wet screed in that it uses a small amount of water necessary to mix the cement-sand mixture.

Therefore, a semi-dry screed is difficult to qualitatively distribute and seal, taking into account the laid floor heating system - mounting tape and heat cable. With a decrease in the density of the cement stone, due to the formation of air cavities, the heating efficiency decreases, because. the thermal conductivity of the screed decreases.

When preparing sand concrete for screed on your own, special attention should be paid to the quality of the ingredients. The sand must be coarse, sifted, free of clay and other harmful impurities (shells, plant remains, pollution by oil products, etc.). When choosing the proportions of the mixture, it should be remembered that sand can be of different humidity, which affects required amount mixing water.

When working with ready-made dry mixes, pay attention to the availability of information with recommendations on basic recipes and the exact proportions for preparing the main types of solutions. This simplifies the work of builders.

It is possible to improve the quality characteristics of sand concrete and screed using plasticizers and fiberglass.

Recommendations for the use of plasticizers and fibers when pouring sand concrete screed

When using a plasticizer, which is added based on the mass of cement, and not weight ready solution, the required amount of mixing water decreases, because The additive has water-reducing properties. It also increases the workability and plasticity of sand concrete. The composition stretches well along the beacons, compacted and smoothed.

1. Pour the dry mixture into a concrete mixer or working container if the work is carried out with a mixer.
2. Enter a small amount of water (1/3 of the recommended) and mix thoroughly.
3. Lightly dampen the fiber and gently fold it into the mixture. Stir thoroughly until the fibers are evenly distributed throughout the solution. When mixing, there should be no "hedgehogs" from the fibers of the fiber.
4. Measure the manufacturer's recommended amount of chemical additive-plasticizer and mix it with the second third of the mixing water. Add to the solution with constant stirring.
5. After 1.5-2 minutes of stirring, introduce additional water to achieve the required mobility. Stir for another 30 seconds.

The use of fiberglass reduces the labor costs associated with reinforcing the screed metal mesh, improves the quality of the screed, and reduces the likelihood of cracking.

Before using polypropylene fiber and plasticizer additives, you should read the manufacturer's recommendations, which are indicated on product packaging, on dosages and precautions when working with these components.

Also needed proper care behind a freshly laid screed. To retain moisture and prevent its rapid evaporation from the surface, a freshly laid screed must be covered with plastic wrap or drafts should be excluded, and periodic moistening should be provided (2-3 times a day during the first week after the screed is installed). This ensures the uniformity of the screed strength gain without the occurrence of internal stresses leading to the formation of cracks. Before styling finish coat the surface of the screed must be dedusted and cleaned of contaminants.

The portal is discussing various.

In the video - the nuances of building a house from warm ceramics and the features of installing a warm floor.

The floor is the possibility of its device simultaneously with the laying of a warm floor.

This is an important point not only for apartments in which the presence of such a heat source option is a pleasant addition to the heating system, but also for private country houses in which this species heating is practically basic.

The underfloor heating screed can be either under the “water” one - connected to the heating system, or under the electric one, heated with electric heating elements. Let's dwell on each of them in more detail.

Screed for electric underfloor heating

When installing an electric underfloor heating, you should first clean and level the surface of the new floor from dust and small debris. Then the waterproofing of the floor is laid. Then, around the entire perimeter, it is necessary to fix a special damper tape, which in the future will provide compensation for the expansion of the floor with an increase in temperature. When the waterproofing and damper tape are installed, it is necessary to provide thermal insulation of the floor with the help of an insulating material.

The material for thermal insulation, based on the purpose of the heating system and the room itself, can be:

• Foamed foil polyethylene;
• Styrofoam;
• Mineral wool.

Due to the fact that the semi-dry screed layer will have sufficient thickness and be reinforced with fiber, laying a reinforcing mesh is not required.

There is a lot of controversy about how the electric underfloor heating is laid - under the screed, in the screed or on the screed? There are really several laying options, depending on the modification of the heating elements. Infrared film floor heating, for example, can be laid on top of the screed, even under the laminate. At the same time, wired floor mats are placed either under the screed, or as a layer in the middle of the screed, or on top of the screed under tile adhesive. The latter option is preferable, but in addition to the overspending of tile adhesive (of course, in the case of illiterate tile laying), there is a risk of cracking on the tile and its lagging during operation. Therefore, special attention should be paid to the qualifications of a specialist who will perform tile work.

In any case, the heating elements are laid with their preliminary distribution throughout the room, depending on the passage of various pipes, as well as on where your furniture will stand in the future. E if the screed is planned over the underfloor heating cable, and all its heating elements are placed in accordance with the preliminary marking, it is necessary to check the entire heating system by connecting it to the mains. If all indicators are normal, then you can proceed to the device of a semi-dry screed, having previously completely disconnected the entire system from the power supply.

It is worth paying attention to one more important point - the first inclusion of a warm floor after laying the screed. In no case should you turn on the warm floor in the first few days after laying and thus dry it. All processes of hydration of cement stone should occur naturally, therefore, the first heating of thermal elements should be carried out at least 10-15 days after laying the screed.

Screed for underfloor heating

Installation of a “water” or hydraulic floor also begins with cleaning and preliminary leveling of the base surface. On the base, we recommend that you make a full-fledged waterproofing of the base with an overlap on the walls, to a height higher than the finish surface by 5-10 cm. Then, a damper tape is installed around the entire perimeter of the room, which performs the task of soundproofing the wall-floor joint, and also prevents the floor from contacting the walls rooms in case of expansion of the screed when heated. Then there is a laying of a layer that provides thermal insulation of the floor, as a material for which, as a rule, foamed foil polyethylene or basalt foil material of the PMBOR type is used.

Following the hydro and thermal insulation, laying pipe clamps follows. As a rule, extruded polystyrene foam serves as a material for clamps, which is also an excellent sound insulation. Installation of pipes takes place according to preliminary marking, in accordance with the size of the room, the material of the walls and ceilings, the type of flooring and the diameter of the pipes. Pipes for the "water" floor are used either from metal-plastic or from cross-linked polyethylene. The room heating system is then tested by connecting to a central point. The number of loops for heating in the system depends on the number of heated rooms.

After laying the pipes and checking the operability of the heating system, you can proceed to the installation of a semi-dry screed. This type of screed is very progressive and simple. As a reinforcing material, fiber is used, as a result of which the laying of a reinforcing mesh in a warm floor screed is not required. When installing this type of screed, high-quality German equipment is used.

Having ordered a screed for electric or water heated floor from us, it will listen to you for more than one decade!

The company "EUROSTROY" professionally performs the installation of a semi-dry screed for both electric and "water" underfloor heating. Our employees have many years of experience in floor screed installation with various systems heating. Having ordered a heat-insulated floor from us, you will be satisfied with high quality of service and the carried-out repair work.

1 What is underfloor heating

Underfloor heating is a highly reliable cable heating system that can be used both as a comfortable floor heating system and as the main heating system. Heating sections of underfloor heating systems are shielded single-core and two-core cables with two layers of insulation, as well as reliable couplings. From traditional methods of heating, where heat is transferred by convection currents, a warm floor has a number of advantages:

• The heating part of the system is hidden in the floor structure, which allows you to increase the usable area and diversify the design of the premises, while the floor covering can be any: tiles, marble, carpet (except for parquet).
• Does not dry out the air in the room, as the heating cable does not have direct contact with the atmosphere.
• Double insulation and shielding braiding of cables allows the use of underfloor heating in rooms of any humidity.

First of all choose your system.

Before starting the installation of a warm floor, we advise you to make sure that you have chosen the system that is right for your room and the desired type of heating (comfort or basic).

1. The main heating system in separate buildings, including in cases where it is not possible to connect to the central heating system. The main heating system involves the use of a more powerful cable and a screed device with a thickness of at least 5 cm. At the same time, the area of ​​\u200b\u200bwarm floors should be at least 70% of the total area of ​​\u200b\u200bthe heated room. The recommended specific power of the system when using a warm floor as the main heating system is from 160–180 W / m 2. For example, a warm floor with a power of 0.19 kW, heating area - 1.2 m 2; check the power: 190 W / 1.2 m 2 = 158 W / m 2.

2. Additional (comfortable) heating system. It is installed together with other types of heaters and is designed to achieve thermal comfort. Most relevant in rooms with cold floors (bathrooms, bathrooms, kitchens, swimming pools) and on the first floors of buildings. The recommended specific power of the system for comfortable floor heating is 120–140 W/m 2 . For example, a warm floor with a power of 0.19 kW, heating area - 1.5 m 2; check the power: 190 W / 1.5 m 2 = 126 W / m 2.

Comply with regulations

Check if the electrical wiring available in your premises allows additional power to be connected. Consider additional electrical devices that can be connected to the same network. Specify also the permissible current of safety devices (automatic devices). We recommend connecting electric heating systems with a power of 2 kW or more through special wiring and a separate machine. We also recommend the use of an RCD with a rated operating current of not more than 30 mA. This is a small device mounted on the electrical panel that monitors the safety of the electrical insulation of your equipment. When underfloor heating is installed in wet rooms (bathrooms, saunas, swimming pools), the screen of the heating section must be connected to the grounding conductor of the mains, to which, in turn, all accessible metal parts must be connected, such as: metal shower trays, metal frames shower cabins, etc.

How to choose a warm floor

• Determine the free area not occupied by furniture and household appliances.
• Retreat from walls and furniture 5–10 cm.
• Pick up a heating mat or section for a free area.
• The area of ​​the heating mat or section heating area must not exceed the free area.
• It is allowed to lay a warm floor under furniture if the height of the legs is not less than 15 cm.
  

Heating cables

The basis of the design of underfloor heating is a heating cable. Outwardly, it resembles radio frequency cables for transmitting television signals, however, its purpose is not to transmit electrical signals or power over a distance, but to convert all 100% of the power flowing through it electric current into warmth. The release of this power per unit length of the cable (specific heat release) is the most important technical parameter heating cables.

Composition of the underfloor heating system

• heating section or heating mat;
• control equipment (thermostat with temperature sensor);
• accessories to facilitate and speed up installation (mounting tape, corrugated plastic tube, etc.);
• thermal insulation.

Underfloor heating section

Heating sections

Heating sections structurally consist of a piece of heating cable of a certain length and so-called. "cold ends" - pieces of ordinary wire connected to the heating cable with a sleeve. Sections can be made of a single-core and two-core cable, while at the ends you should visually see: in single-core sections - two wires on each side (screen and load), in two-core sections - three wires on one side (screen, load, load) .

Cable pitch

calculated as follows:
Laying step (cm) = (100 * S) / L,
where S is the area on which the warm floor is laid, and L is the length of the cable section.
The minimum laying step is 8 cm

Need to remember

Both single-core and double-core heating sections are shielded without fail! They can be used in both dry and wet areas. Two-layer cable insulation is made of non-flammable and non-consumable materials.
These sections are different design features and, accordingly, the methods of laying on the floor surface.

Installation of warm floors

1. Underfloor heating based on heating sections

To install the system you need:

Preparation	2. Make grooves in the wall for the electrical wiring, the mounting ends of the heating section and the tube for the temperature sensor.
thermal insulation	3. Prepare the floor surface (level, clean from debris). 4. Lay thermal insulation.
fasteners	5. Fix the pieces of mounting tape.
installation	6. Lay and secure the heating section. 7. Mount the temperature sensor.
coupler	9. Make the necessary electrical connections. Check for damage to the heating sections and temperature sensor. Measure the resistance of the section and the sensor. Their values ​​must match the passport data. Record the measurement results in the protocol or on the section layout diagram.
coating	10. Pour cement-sand screed. After 72 hours, the floor can be walked on. 11. Lay the decorative flooring of your choice. 12. After complete drying of the screed - 28 days, the "warm floor" system is ready for operation.

Preparation	1. Prepare a place in the wall for installing the thermostat. 2. Make grooves in the wall for the electrical wiring, the mounting ends of the heating section and the tube for the temperature sensor. 3. Prepare the floor surface (level, clean from debris).
installation	4. Prepare a groove in the floor for a temperature sensor with a connecting wire, which is laid in a corrugated tube...
examination	5. Mount the temperature sensor. 6. Lay the heating mat, gluing it to the surface using the adhesive on the underside of the mesh or using self-adhesive aluminum tape.
thermostat setting	7. Make the necessary electrical connections. Check that the heating mat and temperature sensor are not damaged. Measure the resistance of the mat and sensor. Their values ​​must match the passport data. Record the results of the measurements in the protocol or on the layout of the mat. 8. Install thermostat.
tile adhesive	9. Fill the heating mat with a layer of 5-8 mm thick tile fixing mortar and allow it to dry. 10. Mortar the groove on the wall and lay the decorative flooring to your liking. 11. After the mortar for fixing the tiles has completely dried, the ultra-thin warm floor is ready for use.

For rooms where a cement-sand screed has already been made, or it is not possible to lay it, ultra-thin heating mats have been developed, which are electrical cable reduced diameter (up to 3 mm), fixed with a constant step (about 5 cm) on a carrier glass mesh. Heating mats are a ready-made design that excludes the procedure for laying and fastening a heating cable, so their installation is extremely simple. The mat can be easily cut into fragments (without violating the integrity of the heating cable), which allows it to be laid out on a heated area of ​​any shape. Installation even on an old tile is possible. Two-core heating mats are the most high-tech and environmentally friendly ultra-thin warm floors.

Laying a warm floor in a screed is a responsible process that requires a quality approach. The final result, expressed in the uniformity of thermal distribution, the reliability and safety of the structure, as well as in the saving of consumed resources, depends on the correct execution of all actions. Despite the difficulties, all the work can be done by hand, without the involvement of specialists.

The underfloor heating screed has numerous functions, among which are especially distinguished:

1. Full protection of the heating system from various kinds of influences that can lead to damage to the structure.
2. Proper distribution of the generated heat over the surface, as well as increasing the heating efficiency of the entire room.
3. Obtaining the required level of the base for laying decorative facing materials.
4. No need to use bulky heating elements, which significantly reduce the area of ​​​​the object or spoil the appearance.

The efficiency of a warm floor compared to a traditional radiator system is an order of magnitude higher

Thus, a warm floor located in a screed is rational decision helping to create comfortable living conditions. But a number of conditions must be taken into account:

• The thickness of the poured layer. The location of the heating system at the wrong depth eliminates the desired effect and creates numerous problems. That is why all work is divided into two successive stages: the formation of a rough and finishing surface, between which an electric element will be located. But with minimal deviations of the base, only one layer is poured.
• The type and type of screed used. It depends on the technology used.
• Exact observance of all the nuances in the preparation of the mixture and the stages of its filling. The created structure can have several different layers: insulation, waterproofing, reinforcement.
• Safety. Electric floors and water systems require great care and attention. Importance has the correct installation of elements.

The combination of all conditions is the key to a high-quality, reliable and durable result.

Possessing basic knowledge of electrical safety at the level high school, any House master will be able to mount a modern electrical system of underfloor heating

Varieties of compositions for laying the system

For installation of a warm floor in a coupler are used different kinds compositions that are used in different situations, based on their characteristics.

Most popular options:

• Concrete with the addition of fine aggregate. This solution is suitable for subfloor installation or for filling thermal systems on water heating.
• Cement-sand compositions. It is they who allow laying electric underfloor heating. To give the solution additional properties, special plasticizers are added.
• Mixtures with self-leveling effect. They are used to obtain a thin coating, which is necessary at a low height of the room, as well as when installing a screed on a fairly even base.
• To simplify the process, special products for underfloor heating have been developed. Such mixtures have all the necessary characteristics and qualities.

Bulk special mixtures are considered the highest quality, but for budget option cement-sand mortar is quite suitable

Currently, the most widespread wet screed, allowing you to achieve optimal results. But it has a number of significant drawbacks, in particular, the impossibility of quick dismantling without damaging the structure. Also, with the wrong technology, there is a high probability of the appearance of numerous cracks and deformations, so the dry version is gaining more and more popularity.

Features of installing an electric floor

Laying an electric underfloor heating directly depends on the features of the selected elements.

cable technology

This option is a system where a cable is used as a heating element, laid according to a certain pattern.

The principle of work:

The installation of such a system requires strict adherence to the drawn up scheme and the order of connection.

The scheme of installation of electric underfloor heating may change with an increase in the number of circuits, as well as depending on the type of connection (two and three-phase)

Laying heating mats

The technology of laying a warm floor on heating mats is a simpler procedure that does not require compliance with the accuracy of the cable location. This is due to the fact that they are already fixed in a single structure, which must be properly spread on the surface.

Installation features: mesh rolls are rolled out on a prepared base, to rotate the cells are carefully cut so as not to damage the cable. If it is required to bypass the obstacle, then the grid is cut off, and the heating elements are placed at the required distance from each other. The thermostat is connected and the system is checked.

Mats, compared to other electrical systems, are considered one of the most convenient arrangement options.

It is the mats that allow you to fill the screed with a minimum thickness, which significantly reduces the height of the floor.

On a note! Currently, there are infrared electrical systems that are located not in the depth of the screed, but directly on its surface, under the decorative cladding.

Infrared heaters are of good quality and quickly installed, but not suitable for every room and flooring

The general procedure for installing a warm floor

There is a traditional scheme for laying an electric underfloor heating and pouring a screed. When carrying out work on an unprepared basis, the process is divided into three stages:

The middle layer is not always an appropriate solution, so sometimes it is skipped, and the insulation is covered with waterproofing. But be sure to have the heating system at a distance, fixing it on the fittings.

Thermal insulation is not a mandatory option in an insulating pie, but it greatly increases the efficiency of the system.

Filling the screed and installing the system

Full complex installation work is a sequence of actions depending on the specific situation.

The technology of pouring the screed and laying a warm floor in it:

The screed can be replaced with tile adhesive, but this option is only suitable for tiling

Thus, the general technology of laying the structure is not very difficult if the stages are correctly developed.

To understand the process of laying a warm floor in a screed, a training video will help:

Some nuances

For getting quality result it is advisable to follow some rules:

• reinforcement is a mandatory procedure to avoid subsequent cracking;
• a warm floor needs careful preparation of the base, it is placed exclusively on a flat surface;
• the thickness of the screed is affected by the diameter of the cable used for the electrical system, the optimal parameter is a layer from 30 to 50 mm;
• large rooms are separated by special expansion joints;
• when pouring cement mixture it is necessary to wait for it to dry completely, after which you can carry out other work and use a warm floor.

The minimum thickness of the screed for electric underfloor heating is 4.5-8 cm (water systems from 10 cm), according to the recommendations of many manufacturers. But they calculate the parameter based on ideal installation conditions. In reality, a number of conditions affect the height of the screed layer:

• Foundation quality. If this is soil, then the layer height cannot be less than 10 cm. If the base is floor slabs, then the parameter can vary from 3 cm to 6-9 cm (the height is determined by the degree of slab defects);
• Type of electric floor. The cable is laid in a thicker layer of screed - at least 3-4 cm. This guarantees the safe operation of the system. Thermomats and a film floor need only light fixation, therefore, a screed for a warm floor of this class should be no more than 3 cm (assuming a flat surface, it is not performed at all);
• Fill material. Mixtures of sand and cement are poured with a thickness of 4 cm. Self-leveling leveling - 2-2.5 cm.

Proper laying of a warm floor in a screed requires compliance with the basic rule - the base on which the system is mounted must be 100% even. Otherwise, to achieve uniform heating of the air masses from the bottom of the room and prevent overheating, the cable will not break. Therefore, the calculation of the thickness of the screed is carried out taking into account the quality of the surface of the base and the materials used. In total, the height of the floor cake for the electric floor can vary from 4.5 to 8 cm with base defects.

The components of the floor pie under the electric floor heating

Lay the electric underfloor heating in the screed in four stages:

• Black fill.

It serves to completely level the base. Since this is the lowest layer of the floor cake, you need to wait for it to completely solidify. When using cement-sand or concrete mixtures, the layer hardening period will be 28 days.

• Heat insulator installation.

In most cases, manufacturers of underfloor heating under a concrete screed recommend heat-insulating material. The recommendations are worth following. An insulator is required. It can be a substrate made of cork, foam, polypropylene, lavsan metallized fabric, etc. The choice of material depends on the type of air mass heating system. If it is electrical systems, it is more practical to choose 300 micron thick aluminum foil with a protective layer. In the case of a water system, polystyrene foam is more suitable.

According to the technology of laying a warm floor under the screed, the heat insulator will not allow wasting electricity for heating the lower floors and foundations. It is spread on a clean base without debris and dust inclusions. Therefore, the installation of warm water and electric floors must be carried out after plastering the walls and ceiling. Fixation of the insulator strips is carried out by means of glue or adhesive tape, dowels.

• Installation of heating systems.

Proper laying of the electric underfloor heating in the screed is carried out only on the usable area - where there will be no household appliances, stationary structures, furniture without legs. The step and method of laying the cable is taken into account, as well as recommendations for connecting heating mats or infrared film.

• Concrete screed.

It has great importance and thickness of the screed for electric underfloor heating above the system. If cement-sand compositions are used, then the pouring height is from 4 cm, leveling types of solutions - 2 cm. Some infrared film types of floors and heating mats are laid without a thick top layer of the screed. For fixing, for example, tile adhesive or leveling compound is sufficient.

The rules for pouring a floor screed under a warm floor cannot be neglected, because it performs a number of functions - protecting heating elements (cable, pipes, mats) from mechanical damage, uniform heating of the entire usable area, a flat base for flooring. The last point is important for the operation of the coating, because on an uneven base, the finish wears out and deteriorates 3 times faster.

Types of screeds for organizing a warm floor

The terms of work, the features of the base and the selected electric underfloor heating under the screed determine which pouring option to choose. Can be used:

• Wet screed.

We need cement, plasticizer and fine sand. Fiber is added to the resulting solution. The mixture is affordable, easy to mix and stable in use. But it will gain its strength not earlier than in 28-36 days. With uneven solidification, cracks will certainly appear, and therefore, with its help, it is not easy for a non-professional to make a smooth base without defects.

• Semi-dry screed.

Usually ready mixes are used. All that is needed is to add a small amount of water and knead. The mixture is often prepared on its own. You will need river sand, cement and fiber, a plasticizer. A semi-dry screed for an electric underfloor heating is more beneficial, since it does not crack during drying. It is easier for a non-professional to form an ideal surface.

• Dry screed.

The composition depends on the manufacturer. The main components are often fine-grained slag or perlite very fine sand, less often quartz building material. The main advantage of the dry type of mortar is its rapid setting. You can start laying the system after 12-13 hours.

It is possible to turn on the air mass heating system from the bottom of the room only after 100% drying of the mixture. This rule is especially important when using wet formulations. As soon as the screed reaches its maximum strength, high temperatures can't harm her. The operation of the system will be safe and long.

The necessary advice can be obtained on our website. Experienced experts will answer your technical questions in detail.